Q: I’m going to be doing some remote recording with a flash recorder and I’d really like to use the M-S stereo microphone technique.
However, my recorder doesn’t have any kind of M-S setting for flipping the one input out of phase.
Is there any way to do this without dragging along an external preamp?
A: First of all, congratulations on branching out from old recording staple of X-Y! No, seriously!
As you’ve undoubtedly discovered, M-S calls for two outputs from a bi-directional (figure-8) microphone (though other options are possible), one of which is out of phase.
As to how one accomplishes this?
First, you need to get two outputs from the microphone. There are a couple of ways to accomplish this. You can use a “Y” cable between the microphone and the mixer / recorder. You can buy or build a mic cable that is terminated to two XLR male ends.
Or, the preferred method (though not possible in your case) is to use a dedicated high quality microphone preamp and split the signal after it comes out (this is much more robust than splitting the signal out of the microphone itself).
Second, you need to reverse the polarity of one of the outputs (not change the phase as you say above). In the “Y” cable example this is as simple as reversing the wires going to pins “2” and “3” on one of the male XLR connectors.
If using a preamp you would need to reverse those pins on one of the cables connecting the preamp to your mixer or recorder. Many preamps and mixers have a handy polarity reverse switch on each channel you can use instead of modifying cables.
Also, it is possible to buy adapters that will reverse the polarity of a microphone signal, but it really is just as simple as reversing pins “2” and “3” somewhere.
Incidentally, whether you’re buying specialty polarity reversal cables or building your own, be sure to label your cable. That’s not the “Y” cable you want to accidentally grab when you’re setting up in a rush and need a regular “Y.”
For further information on stereo microphone techniques, check out this recent article brought to you by Shure.
As always, we welcome input from the PSW community and would love to know how you would handle M-S in a mobile environment. Feel free to let us know in the comments below.
For more tech tips go to Sweetwater.com
